Method of distillation of petroleum



[Sept 4, 1928. 1,683,135 Y E. w. lrsoM METHOD or DIsTILLATioN or' PETROLEUM P ileduay 6,' 1924 .Y I7 v 7 @Z, A

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A TroRNEY 'l Patented Sept. 4, 1928.

EDWARD W. ISOM, F WINNETKA, ILLINOIS, ASSIGNOB,

TO SINCLAIR REFINING COM- PAN Y, 0F CHICAGO, ILLINOIS, .A CORPORATION OF VILAINE.

METHOD 0F DISTILLATION' OF PETROLEUM.

Application led May 6,

This invention relates to method of distilling crude oil for the production of gasoline or similar light distillate, a heavier distillate of a gas oil character and coke.

In the distillation of crude oil it is customary to subject the oil first to a topping operation for the separation of gasoline, or gasoline and kerosene, therefrom, and thereafter to distill the heavier oil to coke in coke stills. By the usual methods of distillation it is difficult to remove all of thegasoline constituents from the oil, and, in order to insure the recovery of as large an amount of suchconstituents as possible, it is customary to include with the trst light distillate a considerable amount of kerosene constituents so that it is necessary to re-run the light distillate for the recovery of finished gasoline therefrom.

The present invention provides an im- 'proved method of operation whereby sub,- stantially the maximum yield of gasoline p or similar light distillate can be directly obtained in a sin le distillation, and the distillation therea ter continued in the same still for the production of gas oil character fraction and coke.

The invention will be further described in connection with the accompanying drawings illustrating in a somewhat conventional and diagrammatic manner one form of apparatus adapted for the practice of the invention.

In the accom anying drawings,

Fig. 1 shows t e upper part of a still drum with a. helical reux tower mounted thereon; and

Fig. 2 is a view partly in section and partly in elevation taken at right angles to that of Fig. 1.

In the apparatus illustrated a reflux tower 1 is shown as mounted upon and supported by the still 2 which may be a shell still of' ordinary construction, for example, about 14 feet in diameter and about 40 feet long. This stillmay be heated in the customary manner by a furnace chamber (not shown). The reflux tower ma for example, have a height of about 30 eet and with a tower 5o of the type illustrated may have cross sectional dimensions of about 6 by 12 feet. The helical tower illustrated is of the type described in the companion application of John E. Bell, Ser. N o. 703,338 filed April 1,

an improved successive pans in the form 1924. Serial No. 711,376.

The reflux tower illustrated is' of a general helical construction with a central plate -3 dividing the two sides of the tower and with a series of overlapping pans 5 supported at the sides of the tower on rods 4 and suit,- ably secured and supported at the ends of tile1 tower, for example, by welding to the s el.

These overlapping pans 5 form ra generally helical surface over which the oil flows downwardly, and a generally helical path between the successive turns of the helical surface through which the vapors pass up# wardly. The oil collectin in the reflux reservoir 6 at the bottom 0% the helix overflows through the pipe 10, having valve 11 therein, into the still.v This reflux reservoir 6 is separated from the vapor space by the side wall 8 and has a bottom wall 9 located somewhat above the top of the still proper. A draw-off 19 with-valve 20 therein permits the drawing ofll or sampling of the oil from the reservoir 6. Oil is fed into the reflux tower through the supply pipe 7.

The reflux tower connects with the still through the connection 12 and a butterfly valve 13 is provided for shutting olf the reflux tower and still when this is desired. The butterfly valve 13 is operated by a suit,- able handle 24:.l A side connecting pipe 14 with regulating valve therein (not shown) leads directly to a condenser. The vapor outlet 12 may be covered with suitable heatinsulating material 15 and the tower as a whole may be similarly covered, although such insulation is not shown.

Openings 17 in the top 16 of the tower permit access thereto while side openings 18 similarly permit access to intermediate portions of the tower where this is desired. Intermediate draw-off pipes 21 having regulating valves 22 permit the withdrawal of fractions of oil from intermediate portions of the tower where this is desired. A vapor outlet leading to a condenser (not shown) is illustrated at 23. Intermediate valved oonnections 25 permit the introduction of part or all of the feed at intermediate points below the top of the tower where this is desired'. 'The 'refiux tower illustrated is of a 105 construction which permits a close regulation of the vapors escaping therefrom. The oil introduced at the top of the tower, or at intermediate points, flows down over the 0f thin films 0r 110 pools while the vapors rising from the still pass upwardly between the turns of the elix and come into heat interchanging relation both with the downwardly flowing oil 5 and, through the walls of the pans, with the oil in the next upper turn of the helix. This oil is a full turn higher up in the helix than the vapors beneath it, with the result that an increased heat transfer takes place because of the greater difference in temperature than in the case of liquid with which the vapors come into direct contact.

. In the operation of the still and the practice of the improved process of the present i5 invention therein, the still is initially filled only partly full, for example, about onethird full, of crude oil to be distilled. The fires will then be started and vapors driven up into the tower. Refluxing of these vapors will take place and only the lighter vapors will at first reach the top of the tower and escape therefrom. This operation is continued until the va ors begin to become heavier than those o the desired distillate.

With continued heating of the still, the temperature will continue to rise, and crude oil will be then fed into .the tower so as to maintain a ysuitable vapor temperature at the to of the tower, for example, of 350 F.

v This feed of crude oil will be slow at first, and will be increased as the still gets hotter. The still will gradually ill with the charge, lbut with effective refluxing such as that obtainable, the still will be completely freed from all of the gasoline constituents, for example, all of the constituents that will go into 450 end point gasoline.

When all of the gasoline has thus been removed from the still and from the additional crude oil fed into the reflux tower, and when the still has been filled to the point redetermined as the maximum level, the yfeed of crude oil to the tower is shut oifand, shortly afterward, the vapor line at the bottom of the reflux tower will be opened direct to the condenser, after which the vapor line from the reflux tower to the condensers will be closed as well as the buttery valve between the still and the tower and the valve in the overflow line from the reflux reservoir.

The still will now act without the reflux tower and the vapors will pass direct to the condenser, and this operation can be continued until the still charge is run down to coke. After the usual cleaning operation, the still can be again charged and the operation repeated.

In the carrying out of the process, the

0 intimate refluxing action which takes place in thetower permits a substantially complete `separation of gasoline, or of similar light distillate, to be obtained from the crude oil in a single operation, while giving a crude 55 oil residue substantially freed from gasoline constituents, which can then be run directly to coke and a heavy gas oil character distillate obtained suitable for" use as charging 4stock for pressure stills. The heavy fraction so obtained comprises the entire dist`llate between the gasoline or similar light distillate and the undistilled residue, although it will be apparent that this fraction could be collected in separate cuts where this is desired, e. g., the usual gas oil distillate intermediate the gasoline and lubricating oils could be separately collected. This substantially complete separation of gasoline in a single operation eliminates the. necessity for re-running the usual light benzine, or adymixed benzine and kerosene distillate while it neverthelessv recovers the substantially maximum yieldof gasoline from the crude oil and permits the continuation of the distillation without loss of heat and without the necessity for transfer of the oil to a coke still, until the charge is reduced to a coke residue, although it will be evident that the distillation may be stopped before coke is reached, and the residue withdrawn from the still while i'n a liquid state, where this is desired.

I claim;

1. The method of distilling crudel oil which comprises introducing into the still substantially less than a normal charge of the crude oil, heating the ,still and subjecting the vapors therefrom to refluxing action until the desired light distillate is removed from the still charge, then introducing additional crude oil to said still in reiluxing relation with the vapors therefrom and continuing the heating of the still with regulation of the feedto obtain the desired light distillate from the reflux tower, discontinuing the operation when the still is approxmatel lled,

and distilling the resulting charge irectly to a condenser without refluxing until a coke-line residue remains.

2. The method of distilling crude oil which comprises introducing into the still substantially less than a normal charge of the crude oil, heating the still -and subjecting the vapors therefrom to reiluxing action until the desired light distillate is removed from the still charge, then introducing additional crude oil to said still in refluxing relation with the vapors therefrom and continuing theA heating of the/still with regulation of the feed to obtain the desired light distillate from the reflux tower, discontinuing the operation when the still is approximately filled, and distilling the resulting charge directly to a. condenser without refluxing.

3. The method of distilling crude oil to recover therefrom in a ysingle still a gasoline distillate, a gas oil distillate, and coke, which comprises introducing into the still substantially less than the normal charge of crude oil, withdrawing the vapors through a reflux tower and subjecting the same to a sufficient. refluxing operation therein to condense the heavier constituents while permitting the gasoline vapors to escape, beginning the introduction of crude oil to said still in contact with the vapors to increase the refluxing action, and increasing the feed of crude oil as the still temperature rises, regulating the feed of crude oil and the relluxing action to drive off substantially all of the gasoline constituents from the crude oil while condensing the heavier constituents, continuing this operation until the still is substantially full of crude oil from which the gasoline has been removed, then distilling the ,still chargel without refluxing direct to a condenser and continuing the operation until a coke-like residue remains.

4. The method-of distilling crude oil to recover therefrom in a single still a gasoline distillate, a gas oil distillate, and coke, which comprises introducing into the still substantially less than the normal charge of crude oil, withdrawing the vapors through a reflux tower and subjecting the same to a suflicient reuxing operation therein to condense the heavier constituents gasoline vapors to escape, beginning the introduction of crude oil to said stilLin contact with the vapors to increase the refluxing action, and increasing the feed of crude oil as the still temperature rises, regulating the feed of crudeoil and the refluxing action to drive off substantially all of the gasoline constituents frein the crude oil while condensing the heavier constituents, continuing this operation until the still is substantially full of crude oil from which the gasoline has been removed, then distilling the still charge without refluxing direct toa condenser.

In testimony whereof I alix my signature.

EDWARD W. ISOM.

while permitting the y 

